Overweight toddlers and young children are suffering from conditions usually found in much older people such as high blood pressure, knee joint problems, type two diabetes and even blindness in extreme cases, leading obesity experts have warned.
It comes as clinicians warned there has been up to a potential five-fold increase in severe obesity rates since the pandemic.
After appearing to level off before COVID-19 - except for those in disadvantaged areas - the rate of increase in obesity levels among children and teens is accelerating again.
Detailing some of the worrying recent cases she has treated, the clinical lead of the national Child and Adolescent Obesity Service at Temple Street, Dr Grace O'Malley said: 'You'll see fat tissue building up around the heart or the airway so that breathing can be affected - children will be more breathless, have higher rates of asthma, high blood pressure.'
Dr O'Malley said that, at the last count, just under half the children seen at the Temple Street clinic had high blood pressure.
'Many of the kids will develop bad headaches from a build-up of pressure,' Dr O'Malley added. 'Then chronic pain - that's a big problem. That means children and teenagers drop out of school. Around the excess loading joints we can have higher levels of pain, particularly the knees, feet, back pain.'
The obesity expert said non-alcoholic fatty liver disease is 'pretty problematic for a lot of kids because they'll have fatigue, may not sleep as well, they'll have abdominal pain'.
Obstructive sleep apnea is 'pretty common', while 'about three per cent' of children seen have a high risk of type two diabetes.
'If you're developing type-2 diabetes early in life, it's a very serious condition,' she warned. 'We're used to maybe seeing this in 60-year-olds and 70-year-olds, but in the last 15 to 20 years we've started to see that in young adults, then in teenagers, and sometimes even kids younger than 10.'
The paediatric physiotherapist explained that conditions such as breathlessness, high blood pressure, pain, headaches and blurry vision often 'mean that you can't play in the same way as your friends'.
She said: 'You might be a bit slower moving, and breathing might be affected, so you may not be picked for teams, you may not be included in the games in the same way other children would.'
She said in cases that are 'rare, thankfully', she has seen adolescents lose their eyesight because of intracranial pressure - where pressure builds up in the brain thanks to excess fat tissue.
Dr Orla Walsh, adolescent medicine and general paediatrician at Temple Street, agreed the conditions outlined by Dr O'Malley were 'sadly' prevalent in a growing number of young children.
Speaking ahead of the 30th European Congress on Obesity in Dublin this week, she said the rate of obesity among primary school pupils was 'levelling off' before the Covid-19 emergency, except for children at disadvantaged schools, where it is increasing.
In line with other western countries, children here in Deis schools [for disadvantaged children] have double the risk of developing obesity.
Dr O'Malley, the lead of the Obesity Research and Care Group in the Royal College of Surgeons Ireland, said indications from other countries around the impact of the pandemic were 'very worrying' and likely to be mirrored here.
She said: 'In the UK they look at kids coming into primary school and when they leave, and usually the rate of increase in obesity was around 1% each year before 2020. Since 2020, that's gone up to between 3% and 5%.
'Then when you look at severe obesity, which is even more worrying, that went up from about 0.4% to around 3%.'
For deprived children, there was 'three to four times the increase in obesity rates after the pandemic'.
'That's also repeated in Sweden, and it's also repeated in Italy,' she said. 'So more than likely the same thing has happened here.'
Dr O'Malley stressed 'not every child who has a large body will develop obesity'.
She added: 'That's a really important thing for parents to understand. It's not just about the shape or the size of the child; you have to look at all the different metrics - look at their breathing, their blood pressure and their fitness levels.'
Asked what needs to be done to tackle childhood obesity, the clinician-scientist called for regulation of online advertising, labelling the digital environment 'an absolute disaster for promotion of health'.
She said our built environments should be obliged to incorporate play areas and safe passages for children to walk or cycle to school.
'Over 60% of children are driven to school and we don't need to have that,' she stated. 'When you speak to people from the south of Germany, they can't understand why the community would accept that everybody's driving to school. It makes a big difference to traffic and health - moving, playing, getting to know your friends.'
The Health Service Executive (HSE) clinical lead on obesity, Professor Donal O'Shea, said he was 'delighted with the timing' of next week's conference.
A spokesman for the Department of Health said the 'high levels of overweight and obesity among the population, and in particular children and adolescents, are a concern right across Government'.
He said Ireland is 'co-leading on a [European Union] work package called Best practices in reducing marketing of unhealthy food products to children and adolescents'.